31696561 has 16 divisors (see below), whose sum is σ = 35018368. Its totient is φ = 28512000.

The previous prime is 31696559. The next prime is 31696589. The reversal of 31696561 is 16569613.

It is a cyclic number.

It is not a de Polignac number, because 31696561 - 2¹ = 31696559 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 31696561.

It is not an unprimeable number, because it can be changed into a prime (31696591) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 131401 + ... + 131641.

It is an arithmetic number, because the mean of its divisors is an integer number (2188648).

Almost surely, 2^31696561 is an apocalyptic number.

It is an amenable number.

31696561 is a deficient number, since it is larger than the sum of its proper divisors (3321807).

31696561 is a wasteful number, since it uses less digits than its factorization.

31696561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 472.

The product of its digits is 29160, while the sum is 37.

The square root of 31696561 is about 5629.9698933476. The cubic root of 31696561 is about 316.4735229713.

It can be divided in two parts, 3169 and 6561, that added together give a triangular number (9730 = T₁₃₉).

The spelling of 31696561 in words is "thirty-one million, six hundred ninety-six thousand, five hundred sixty-one".